DIY Guide- Using Dual PSU to power a single PC

So you got your processor pumping to 4Ghz+,A Raid 0 Array too!,Good.What? your 550W PSU hesitating to run those Voltmodded 7800 GTX SLi?Random reboots after setting up water cooling?Worry Not!!

This guide shows how to use two ATX PSU to Juice up your Ultra end PC.Double the power,Double the fun,Right?

#Disclaimer:As with every good guide, lets start with a Disclaimer.This mod includes playing with Dangerous voltage levels,tools that may hurt or kill you.PSU have High Uf capacitors installed, these store current and can possibly paralyse or kill a fellow even when turned off!.Unknowingly you may void the hell out of any warranty that may be present.Read the whole guide carefully before attempting any thing.Proceed at your risk,I am in no way responsible for any mishaps due to attempt or use of this guide.If you are struck at some point,I am here at bhvm333@fastmail.fm ,ready to help you.

#Purpose-This method uses two PSUs.One will be called as PSU1 that will power the motherboard(Yes those 7800GTX too).Other PSU(PSU2) will be used to keep those RAID arrays,DVD burners,Fans,Lights and water cooling pumps turning.Sounds quite easy?,but the problem is that the PSU2 will not boot,as it is not connected to the Mainboard,and from there to the power swicth.Read on!.

#Getting hands dirty-1.Firstly get the relay and solder/tape wires to all four points on the relay,shown here(you may use diffrent color codes)->+12V=Yellow>Ground=Black>Switch short1=Green.>Switch shotr2=Blue.Put heat shrink tubing or Tape on the joints.

2.Find the 4 pin Female Molex connector.Connect the +12v&Ground wires from the relay,respectively to the yellow and black wires on the Female molex.Cover the joints as usual.ORCut a Molex connector from PSU1,connect the yellow and black wires directly 'From' PSU1 'To' the respective points on the Relay.(Forget about any warranty now)

3.Get the Female ATX 20 pin connector.Connect it to the Male 20 pin connector of PSU2.

4.Look for a Green wire in the bunch,notice on which pin, among 20 Pins it is connected.Mark this pin on the Female connector.Also mark any one of many black wire connecting pins on the same connector.There are many black wires,so spotting them is easy.

5.Disconnect the connectors,keep PSU aside for a while.

6.As you know where the green and black wires are present on the Connector,Solder green and Blue wires to the Detached Female connector according to the markings.Tape them as usual.

7.Solder these newly joined green & Blue wire to the respective points on the Relay(any of Switch short)ORCut the Green and any of black wires from PSU2 ATX20 pin connector.Join these wires directly to the 'swicth short' points on the Relay(Voids warranty)

PSU are ready!

#Connections-1.Connect the ATX 20 pin connector from PSU1 to the Mainboard.

(You are done if you did not use optional connectors and joined the wires directly)

4.Join recently made ATX 20 pin Female Connector to PSU2,We have already joined it to the 'Switch short' pins on the relay.

5.Plug in 4 Pin Female Molex,we just made, to the free molex connector of PSU1.Those wires will power the Relay.

6.Connect both PSU to the wall sockets(or UPS)

#Powering UP!-If everything went in order,the PC will boot as usual.It will be only more stable than before!!.You will hear the Relay click when it starts.That says it is alive!.Now What?Stop admirng and start pumping VCore!!!

#Beneifits of 'Relay and brother' method-1.You have much more power now.Two 500W PSU can give 1Kw(!!!) of blasting power in this way.2.You are using the connectors hence,not voiding the warranty if done correctly.3You can remove this setup in a Jiffy.4.After disconnecting,you can use PSUs just as normal.5.This system is very portable,Just move the Realy,with both connectors where you need them!

#The Math behind-Overclocked components need much more power than usual.On some day you may hit on the the fact that even 550W PSU is unable to maintain stable voltages.The idea is simple,'Divide and Rule'.We are dividing the load upon two PSUs that will naturally give more power and stablity than single unit.Every standard ATX PSU have a Green wire that signals 'Power on' to the PSU when computer boots up.This wire is connected through the motherboard to the power switch on the cabinet.As we want to turn on second PSU too,I used a relay that will act as an automatic power on swicth.This relay consumes power from PSU1 Molex connector.When the PSU1 boots up,Relay gets activated alongwith.This relay then turns on PSU2 by shorting its Green and Ground wire.PSU2 boots up as a result.All this process happens in a splitsecond,both PSUs appear to boot simultaneously.SIMPLE!!

#Important Tips-1PSU store enough current that can give a nasty shock if you are not careful.Disconnect the PSU from wall socket,then press the PC boot swich once,this will discharge any charge that may be stored.Turn on the monitor too,if it is plugged through the PSU.I strongly recommend rubber gloves and foot wear though.

2.Two PSU may not fit in a regular case.They will also generate much more heat(Which may hamper overclocking).You may want to keep the PSUs outside the case and run only the needed wires into the case.

3.If you are keeping PSU outside the Case,Fit a nice 120mm Fan in the empty area,where PSU generally fits.This will greatly help the airflow.

4.If somehow you managed to fix two PSUs in the case,bundle off the wires,as there will be a big mess.

5.Relay is the heart of this system,Use only high quality Relays to ensure clean power.I suggest the ones that are used to control Car A/C Compressors.